Measure real-world distances in any image
Free online tool for floor plans, blueprints, maps, and photos. No installation. No account. Your images never leave your device.
Start MeasuringHow it works
1. Upload an image
Drag and drop any image onto the canvas. Supports JPEG, PNG, WebP, GIF, BMP, and TIFF. Multiple images can be layered together.
2. Calibrate the scale
Click two points whose real-world distance you know. Enter the measurement and unit. One calibration unlocks every other distance in the image.
3. Measure and export
Click any two points to measure. Add labels, manage layers, and export your annotated canvas as PNG, CSV, or TXT.
Features
Pixel-perfect calibration
Calibrate using any known distance — a door width, a wall length, a printed scale bar. Supports line and diameter modes.
Multi-layer canvas
Upload multiple images and arrange them on an infinite canvas. Toggle visibility, reorder layers, and measure across them.
Multiple export formats
Export annotated images as PNG, measurement tables as CSV, or plain text summaries. All processing happens in your browser.
Session persistence
Your work is automatically saved in browser local storage. Close the tab and come back later — everything will be exactly as you left it.
Popular use cases
Floor plans & apartments
Upload a floor plan image, calibrate using a known wall or door width, and measure every room, corridor, and doorway in minutes.
Construction blueprints
Work with scanned architectural drawings and technical plans. Calibrate against a printed scale bar and extract every dimension.
Room photos & interiors
Calibrate using a standard door height and estimate furniture dimensions, wall widths, and ceiling heights from photographs.
Maps & geographic data
Measure distances on screenshots from Google Maps, cadastral maps, and historical cartography using the built-in scale bar.
Guides & resources
Help · Calibration
How to Calibrate the Scale of an Image to Measure It
Learn what image scale calibration is, why every measurement depends on it, and how to set it in MetricCanvas with a line or a circle diameter.
Read more →Help · Measure tool
How to Measure Distances on an Image Online
Use the MetricCanvas measure tool to draw lines on a photo or plan, read real lengths, keep exact angles and label each measurement.
Read more →Help · Circle tool
How to Measure the Diameter or Radius of a Circle on an Image
Use the circle tool to measure round objects on photos and plans — tables, pipes, columns, tanks or roundabouts — by diameter or by radius.
Read more →Help · Navigation
MetricCanvas Navigation and Keyboard Shortcuts
Every way to move around the infinite canvas: trackpad, Magic Mouse, mouse wheel, touch and keyboard shortcuts for zoom, pan and drawing.
Read more →Frequently asked questions
- Is MetricCanvas free to use?
- Yes, completely free. There is no registration, no subscription, and no usage limit. The tool is supported by non-intrusive advertising shown alongside the canvas.
- Does it work offline?
- Once the page has loaded, MetricCanvas works without an internet connection. Your images and measurements are stored locally in your browser and persist between sessions, so you can close the tab and return to your work later.
- What image formats are supported?
- MetricCanvas accepts any format your browser can render natively — JPEG, PNG, WebP, GIF, BMP, and SVG. There is no file size limit enforced by the tool, though very large images depend on your device's available memory.
- How accurate are the measurements?
- Accuracy depends on the quality of your calibration reference. A clearly defined distance — such as a door frame of known width, a printed scale bar, or a ruler placed in the photograph — produces precise results. Images taken at an angle, with lens distortion, or without a reliable reference will reduce accuracy.
- Are my images uploaded to a server?
- No. MetricCanvas processes everything locally in your browser using standard web APIs. Your images are never sent to any server. This makes it safe to use with confidential architectural plans, proprietary engineering drawings, or any sensitive material.
- Can I work with multiple images at the same time?
- Yes. You can upload multiple images onto the same canvas, set an independent calibration for each one, and draw measurements across all of them. The Layers panel lets you organise and toggle the visibility of each image independently.
- Can I calibrate using a circle or round object?
- Yes. In addition to a straight line between two points, MetricCanvas supports circle-diameter calibration. If you have a round object of known diameter visible in your image — a coin, a wheel, a pipe — you can use it as your calibration reference.
- Is there a mobile version?
- MetricCanvas is responsive and works on mobile browsers. The interface adapts to smaller screens with a compact toolbar and a collapsible panel. For precise measurement work, a desktop or tablet with a larger screen is recommended.